[PATCH] lib/ring: do not allow zero size ring

[PATCH] lib/ring: do not allow zero size ring

[Isaac Boukris]

this might happen when for instance the ring size is read from
config, and would cause runtime crash.

Signed-off-by: Isaac Boukris <iboukris@gmail.com>
---
 app/test/test_ring.c | 7 +++++++
 lib/ring/rte_ring.c  | 4 ++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/app/test/test_ring.c b/app/test/test_ring.c
index ba1fec1de3..81231ecfc2 100644
--- a/app/test/test_ring.c
+++ b/app/test/test_ring.c
@@ -505,6 +505,13 @@ test_ring_negative_tests(void)
 	struct rte_ring *rt = NULL;
 	unsigned int i;
 
+        /* Test zero size ring */
+	rp = test_ring_create("test_zero_size_ring", -1, 0, SOCKET_ID_ANY, 0);
+	if (rp != NULL) {
+		printf("Test failed to detect zero size ring\n");
+		goto test_fail;
+	}
+
 	/* Test with esize not a multiple of 4 */
 	rp = test_ring_create("test_bad_element_size", 23,
 				RING_SIZE + 1, SOCKET_ID_ANY, 0);
diff --git a/lib/ring/rte_ring.c b/lib/ring/rte_ring.c
index edd63aa535..f9434de536 100644
--- a/lib/ring/rte_ring.c
+++ b/lib/ring/rte_ring.c
@@ -67,7 +67,7 @@ rte_ring_get_memsize_elem(unsigned int esize, unsigned int count)
 	}
 
 	/* count must be a power of 2 */
-	if ((!POWEROF2(count)) || (count > RTE_RING_SZ_MASK )) {
+	if ((count == 0) || (!POWEROF2(count)) || (count > RTE_RING_SZ_MASK )) {
 		RING_LOG(ERR,
 			"Requested number of elements is invalid, must be power of 2, and not exceed %u",
 			RTE_RING_SZ_MASK);
@@ -227,7 +227,7 @@ rte_ring_init(struct rte_ring *r, const char *name, unsigned int count,
 		r->mask = r->size - 1;
 		r->capacity = count;
 	} else {
-		if ((!POWEROF2(count)) || (count > RTE_RING_SZ_MASK)) {
+		if ((count == 0) || (!POWEROF2(count)) || (count > RTE_RING_SZ_MASK)) {
 			RING_LOG(ERR,
 				"Requested size is invalid, must be power of 2, and not exceed the size limit %u",
 				RTE_RING_SZ_MASK);
-- 
2.49.0

[PATCH v2] lib/ring: do not allow zero size ring

[Isaac Boukris]

this might happen when for instance the ring size is read from
config, and would cause runtime crash.

Signed-off-by: Isaac Boukris <iboukris@gmail.com>
---

v2:
* move the fix to the POWEROF2 macro itself.
* fixed style in the test code.

 app/test/test_ring.c | 7 +++++++
 lib/ring/rte_ring.c  | 2 +-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/app/test/test_ring.c b/app/test/test_ring.c
index ba1fec1de3..3078348b2f 100644
--- a/app/test/test_ring.c
+++ b/app/test/test_ring.c
@@ -505,6 +505,13 @@ test_ring_negative_tests(void)
 	struct rte_ring *rt = NULL;
 	unsigned int i;
 
+	/* Test zero size ring */
+	rp = test_ring_create("test_zero_size_ring", -1, 0, SOCKET_ID_ANY, 0);
+	if (rp != NULL) {
+		printf("Test failed to detect zero size ring\n");
+		goto test_fail;
+	}
+
 	/* Test with esize not a multiple of 4 */
 	rp = test_ring_create("test_bad_element_size", 23,
 				RING_SIZE + 1, SOCKET_ID_ANY, 0);
diff --git a/lib/ring/rte_ring.c b/lib/ring/rte_ring.c
index edd63aa535..0a9fc31530 100644
--- a/lib/ring/rte_ring.c
+++ b/lib/ring/rte_ring.c
@@ -47,7 +47,7 @@ EAL_REGISTER_TAILQ(rte_ring_tailq)
 		     RING_F_MP_HTS_ENQ | RING_F_MC_HTS_DEQ)
 
 /* true if x is a power of 2 */
-#define POWEROF2(x) ((((x)-1) & (x)) == 0)
+#define POWEROF2(x) ((x != 0) && (((x)-1) & (x)) == 0)
 
 /* by default set head/tail distance as 1/8 of ring capacity */
 #define HTD_MAX_DEF	8
-- 
2.49.0

Re: [PATCH v2] lib/ring: do not allow zero size ring

[Wathsala Vithanage]

On 11/10/25 17:15, Isaac Boukris wrote:
> this might happen when for instance the ring size is read from
> config, and would cause runtime crash.
>
> Signed-off-by: Isaac Boukris <iboukris@gmail.com>
> ---
>
> v2:
> * move the fix to the POWEROF2 macro itself.
> * fixed style in the test code.
>
>   app/test/test_ring.c | 7 +++++++
>   lib/ring/rte_ring.c  | 2 +-
>   2 files changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/app/test/test_ring.c b/app/test/test_ring.c
> index ba1fec1de3..3078348b2f 100644
> --- a/app/test/test_ring.c
> +++ b/app/test/test_ring.c
> @@ -505,6 +505,13 @@ test_ring_negative_tests(void)
>   	struct rte_ring *rt = NULL;
>   	unsigned int i;
>   
> +	/* Test zero size ring */
> +	rp = test_ring_create("test_zero_size_ring", -1, 0, SOCKET_ID_ANY, 0);
> +	if (rp != NULL) {
> +		printf("Test failed to detect zero size ring\n");
> +		goto test_fail;
> +	}
> +
>   	/* Test with esize not a multiple of 4 */
>   	rp = test_ring_create("test_bad_element_size", 23,
>   				RING_SIZE + 1, SOCKET_ID_ANY, 0);
> diff --git a/lib/ring/rte_ring.c b/lib/ring/rte_ring.c
> index edd63aa535..0a9fc31530 100644
> --- a/lib/ring/rte_ring.c
> +++ b/lib/ring/rte_ring.c
> @@ -47,7 +47,7 @@ EAL_REGISTER_TAILQ(rte_ring_tailq)
>   		     RING_F_MP_HTS_ENQ | RING_F_MC_HTS_DEQ)
>   
>   /* true if x is a power of 2 */
> -#define POWEROF2(x) ((((x)-1) & (x)) == 0)
> +#define POWEROF2(x) ((x != 0) && (((x)-1) & (x)) == 0)
>   
>   /* by default set head/tail distance as 1/8 of ring capacity */
>   #define HTD_MAX_DEF	8

Acked-by: Wathsala Vithanage <wathsala.vithanage@arm.com>

RE: [PATCH v2] lib/ring: do not allow zero size ring

[Morten Brørup]

> diff --git a/lib/ring/rte_ring.c b/lib/ring/rte_ring.c
> index edd63aa535..0a9fc31530 100644
> --- a/lib/ring/rte_ring.c
> +++ b/lib/ring/rte_ring.c
> @@ -47,7 +47,7 @@ EAL_REGISTER_TAILQ(rte_ring_tailq)
>  		     RING_F_MP_HTS_ENQ | RING_F_MC_HTS_DEQ)
> 
>  /* true if x is a power of 2 */
> -#define POWEROF2(x) ((((x)-1) & (x)) == 0)
> +#define POWEROF2(x) ((x != 0) && (((x)-1) & (x)) == 0)

Please remove this private macro and use the RTE_IS_POWER_OF_2() macro from rte_bitops.h instead.
With such modification,
Acked-by: Morten Brørup <mb@smartsharesystems.com>

<feature creep>
app/pdump/main.c also defines a POWEROF2() macro, which could be replaced by RTE_IS_POWER_OF_2().
But changing that is unrelated to your improvement in this patch, and should be an independent patch.
Not your responsibility to fix that; just mentioning it for someone to pick it up.
</feature creep>

[PATCH v3] lib/ring: do not allow zero size ring

[Isaac Boukris]

this might happen when for instance the ring size is read from
config, and would cause runtime crash. Do so by using the
RTE_IS_POWER_OF_2 macro.

Signed-off-by: Isaac Boukris <iboukris@gmail.com>
Acked-by: Wathsala Vithanage <wathsala.vithanage@arm.com>
Acked-by: Morten Brørup <mb@smartsharesystems.com>
---

v3:
* changed to use the RTE_IS_POWER_OF_2 macro.

v2:
* move the fix to the POWEROF2 macro itself.
* fixed style in the test code.

 app/test/test_ring.c | 7 +++++++
 lib/ring/rte_ring.c  | 8 +++-----
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/app/test/test_ring.c b/app/test/test_ring.c
index ba1fec1de3..3078348b2f 100644
--- a/app/test/test_ring.c
+++ b/app/test/test_ring.c
@@ -505,6 +505,13 @@ test_ring_negative_tests(void)
 	struct rte_ring *rt = NULL;
 	unsigned int i;
 
+	/* Test zero size ring */
+	rp = test_ring_create("test_zero_size_ring", -1, 0, SOCKET_ID_ANY, 0);
+	if (rp != NULL) {
+		printf("Test failed to detect zero size ring\n");
+		goto test_fail;
+	}
+
 	/* Test with esize not a multiple of 4 */
 	rp = test_ring_create("test_bad_element_size", 23,
 				RING_SIZE + 1, SOCKET_ID_ANY, 0);
diff --git a/lib/ring/rte_ring.c b/lib/ring/rte_ring.c
index edd63aa535..f10050a1c4 100644
--- a/lib/ring/rte_ring.c
+++ b/lib/ring/rte_ring.c
@@ -25,6 +25,7 @@
 #include <rte_string_fns.h>
 #include <rte_tailq.h>
 #include <rte_telemetry.h>
+#include <rte_bitops.h>
 
 #include "rte_ring.h"
 #include "rte_ring_elem.h"
@@ -46,9 +47,6 @@ EAL_REGISTER_TAILQ(rte_ring_tailq)
 		     RING_F_MP_RTS_ENQ | RING_F_MC_RTS_DEQ |	       \
 		     RING_F_MP_HTS_ENQ | RING_F_MC_HTS_DEQ)
 
-/* true if x is a power of 2 */
-#define POWEROF2(x) ((((x)-1) & (x)) == 0)
-
 /* by default set head/tail distance as 1/8 of ring capacity */
 #define HTD_MAX_DEF	8
 
@@ -67,7 +65,7 @@ rte_ring_get_memsize_elem(unsigned int esize, unsigned int count)
 	}
 
 	/* count must be a power of 2 */
-	if ((!POWEROF2(count)) || (count > RTE_RING_SZ_MASK )) {
+	if ((!RTE_IS_POWER_OF_2(count)) || (count > RTE_RING_SZ_MASK)) {
 		RING_LOG(ERR,
 			"Requested number of elements is invalid, must be power of 2, and not exceed %u",
 			RTE_RING_SZ_MASK);
@@ -227,7 +225,7 @@ rte_ring_init(struct rte_ring *r, const char *name, unsigned int count,
 		r->mask = r->size - 1;
 		r->capacity = count;
 	} else {
-		if ((!POWEROF2(count)) || (count > RTE_RING_SZ_MASK)) {
+		if ((!RTE_IS_POWER_OF_2(count)) || (count > RTE_RING_SZ_MASK)) {
 			RING_LOG(ERR,
 				"Requested size is invalid, must be power of 2, and not exceed the size limit %u",
 				RTE_RING_SZ_MASK);
-- 
2.49.0

RE: [PATCH v3] lib/ring: do not allow zero size ring

[Konstantin Ananyev]

> this might happen when for instance the ring size is read from
> config, and would cause runtime crash. Do so by using the
> RTE_IS_POWER_OF_2 macro.
> 
> Signed-off-by: Isaac Boukris <iboukris@gmail.com>
> Acked-by: Wathsala Vithanage <wathsala.vithanage@arm.com>
> Acked-by: Morten Brørup <mb@smartsharesystems.com>
> ---
> 
> v3:
> * changed to use the RTE_IS_POWER_OF_2 macro.
> 
> v2:
> * move the fix to the POWEROF2 macro itself.
> * fixed style in the test code.
> 
>  app/test/test_ring.c | 7 +++++++
>  lib/ring/rte_ring.c  | 8 +++-----
>  2 files changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/app/test/test_ring.c b/app/test/test_ring.c
> index ba1fec1de3..3078348b2f 100644
> --- a/app/test/test_ring.c
> +++ b/app/test/test_ring.c
> @@ -505,6 +505,13 @@ test_ring_negative_tests(void)
>  	struct rte_ring *rt = NULL;
>  	unsigned int i;
> 
> +	/* Test zero size ring */
> +	rp = test_ring_create("test_zero_size_ring", -1, 0, SOCKET_ID_ANY, 0);
> +	if (rp != NULL) {
> +		printf("Test failed to detect zero size ring\n");
> +		goto test_fail;
> +	}
> +
>  	/* Test with esize not a multiple of 4 */
>  	rp = test_ring_create("test_bad_element_size", 23,
>  				RING_SIZE + 1, SOCKET_ID_ANY, 0);
> diff --git a/lib/ring/rte_ring.c b/lib/ring/rte_ring.c
> index edd63aa535..f10050a1c4 100644
> --- a/lib/ring/rte_ring.c
> +++ b/lib/ring/rte_ring.c
> @@ -25,6 +25,7 @@
>  #include <rte_string_fns.h>
>  #include <rte_tailq.h>
>  #include <rte_telemetry.h>
> +#include <rte_bitops.h>
> 
>  #include "rte_ring.h"
>  #include "rte_ring_elem.h"
> @@ -46,9 +47,6 @@ EAL_REGISTER_TAILQ(rte_ring_tailq)
>  		     RING_F_MP_RTS_ENQ | RING_F_MC_RTS_DEQ |	       \
>  		     RING_F_MP_HTS_ENQ | RING_F_MC_HTS_DEQ)
> 
> -/* true if x is a power of 2 */
> -#define POWEROF2(x) ((((x)-1) & (x)) == 0)
> -
>  /* by default set head/tail distance as 1/8 of ring capacity */
>  #define HTD_MAX_DEF	8
> 
> @@ -67,7 +65,7 @@ rte_ring_get_memsize_elem(unsigned int esize, unsigned int
> count)
>  	}
> 
>  	/* count must be a power of 2 */
> -	if ((!POWEROF2(count)) || (count > RTE_RING_SZ_MASK )) {
> +	if ((!RTE_IS_POWER_OF_2(count)) || (count > RTE_RING_SZ_MASK)) {
>  		RING_LOG(ERR,
>  			"Requested number of elements is invalid, must be power of
> 2, and not exceed %u",
>  			RTE_RING_SZ_MASK);
> @@ -227,7 +225,7 @@ rte_ring_init(struct rte_ring *r, const char *name, unsigned
> int count,
>  		r->mask = r->size - 1;
>  		r->capacity = count;
>  	} else {
> -		if ((!POWEROF2(count)) || (count > RTE_RING_SZ_MASK)) {
> +		if ((!RTE_IS_POWER_OF_2(count)) || (count > RTE_RING_SZ_MASK))
> {
>  			RING_LOG(ERR,
>  				"Requested size is invalid, must be power of 2, and
> not exceed the size limit %u",
>  				RTE_RING_SZ_MASK);
> --

Acked-by: Konstantin Ananyev <konstantin.ananyev@huawei.com>

> 2.49.0

Re: [PATCH v3] lib/ring: do not allow zero size ring

[Thomas Monjalon]

11/11/2025 09:24, Konstantin Ananyev:
> 
> > this might happen when for instance the ring size is read from
> > config, and would cause runtime crash. Do so by using the
> > RTE_IS_POWER_OF_2 macro.
> > 
> > Signed-off-by: Isaac Boukris <iboukris@gmail.com>
> > Acked-by: Wathsala Vithanage <wathsala.vithanage@arm.com>
> > Acked-by: Morten Brørup <mb@smartsharesystems.com>
> 
> Acked-by: Konstantin Ananyev <konstantin.ananyev@huawei.com>

Applied, thanks.